Are you vaping PG or VG or a blend? What nicotine%? Is the eliquid a flavor and brand you've had before? Do you notice any bad taste? I got a 100%VG once and they added too much ethyl alcohol to it. I could've puked if I would've kept vaping it. Instead, I'm letting it sit a week with the lid off. But the alcohol issue also had a horrible flavor.
Ah, yeah; that's a good one; maybe it was some juice that really needed to steep first to evaporate.